http: control GSSAPI credential delegation

Delegation of credentials is disabled by default in libcurl since
version 7.21.7 due to security vulnerability CVE-2011-2192. Which
makes troubles with GSS/kerberos authentication when delegation
of credentials is required. This can be changed with option
CURLOPT_GSSAPI_DELEGATION in libcurl with set expected parameter
since libcurl version 7.22.0.

This patch provides new configuration variable http.delegation
which corresponds to curl parameter "--delegation" (see man 1 curl).

The following values are supported:

* none (default).
* policy
* always

Signed-off-by: Petr Stodulka <pstodulk@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/http.c b/http.c
index cd40b012f8..624f0ce65d 100644
--- a/http.c
+++ b/http.c
@@ -90,6 +90,18 @@ static struct {
 	 * here, too
 	 */
 };
+#if LIBCURL_VERSION_NUM >= 0x071600
+static const char *curl_deleg;
+static struct {
+	const char *name;
+	long curl_deleg_param;
+} curl_deleg_levels[] = {
+	{ "none", CURLGSSAPI_DELEGATION_NONE },
+	{ "policy", CURLGSSAPI_DELEGATION_POLICY_FLAG },
+	{ "always", CURLGSSAPI_DELEGATION_FLAG },
+};
+#endif
+
 static struct credential proxy_auth = CREDENTIAL_INIT;
 static const char *curl_proxyuserpwd;
 static const char *curl_cookie_file;
@@ -316,6 +328,15 @@ static int http_options(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (!strcmp("http.delegation", var)) {
+#if LIBCURL_VERSION_NUM >= 0x071600
+		return git_config_string(&curl_deleg, var, value);
+#else
+		warning(_("Delegation control is not supported with cURL < 7.22.0"));
+		return 0;
+#endif
+	}
+
 	if (!strcmp("http.pinnedpubkey", var)) {
 #if LIBCURL_VERSION_NUM >= 0x072c00
 		return git_config_pathname(&ssl_pinnedkey, var, value);
@@ -622,6 +643,22 @@ static CURL *get_curl_handle(void)
 	curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 #endif
 
+#if LIBCURL_VERSION_NUM >= 0x071600
+	if (curl_deleg) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(curl_deleg_levels); i++) {
+			if (!strcmp(curl_deleg, curl_deleg_levels[i].name)) {
+				curl_easy_setopt(result, CURLOPT_GSSAPI_DELEGATION,
+						curl_deleg_levels[i].curl_deleg_param);
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(curl_deleg_levels))
+			warning("Unknown delegation method '%s': using default",
+				curl_deleg);
+	}
+#endif
+
 	if (http_proactive_auth)
 		init_curl_http_auth(result);